Platinum-based catalyst as well as preparation method and application thereof
Synthesize nanorod-shaped support by polyphenols and homotriazine-based compounds and depositing platinum nanoparticles, solving the problem of complex preparation and insufficient stability of existing carbon support materials, achieving high activity and stability of platinum-based catalysts, reducing the Production cost and energy consumption.
Patent Information
- Application Number
- CN202411480513.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-23
- Publication Date
- 2024-12-06
AI Technical Summary
The existing carbon support materials have problems such as high temperature calcination, complex process flow and high cost during the preparation process, and their stability and dispersion in a strong acid environment are insufficient, which affects the catalytic activity and stability of the platinum-based catalyst.
The nanorod-shaped support is synthesized by supramolecular self-assembly method using polyphenols and homotriazine-based compounds, and platinum nanoparticles are deposited on the surface of the support through reducing acids or alcohols to form platinum-based catalysts, which avoids high temperatures and complex processes and improves the Dispersibility and catalytic activity of platinum nanoparticles.
The high activity and stability of the platinum-based catalyst under normal temperature and pressure is achieved, production costs and energy consumption are reduced, and the use of surfactants is eliminated, and it has good corrosion resistance and mechanical strength.
Smart Images
Figure CN119076063A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of nanocomposite material preparation, and in particular to a platinum-based catalyst and a preparation method and application thereof. Background Art
[0002] At present, the most commonly used catalysts for formic acid redox are mainly platinum-based catalysts and palladium-based catalysts. Platinum metal is easy to agglomerate. In order to prevent irreversible agglomeration of platinum metal particles in the catalyst and improve its dispersibility, it is usually necessary to load metal nanoparticles on a carrier. The properties of the carrier affect the particle size and dispersion of the metal nanoparticles and thus affect the catalytic activity and stability of the entire catalyst. Therefore, a good carrier is of great significance to the catalytic performance of the platinum-based catalyst.
[0003] Carbon materials are often selected as catalyst carriers due to their good conductivity, large specific surface area, rich functional groups and pore structure. Commonly used carbon carriers include carbon black, graphene, mesoporous carbon and carbon nanotubes, etc. However, these carriers have their own limitations. Carbon black, as the most commonly used carbon carrier, is generally obtained by pyrolysis of hydrocarbons. Its surface contains impurities such as organic sulfur that are difficult to remove. It is unstable in a strong acid environment and is easily corroded, which accelerates the separation of the active components of the catalyst from the carrier; the two-dimensional graphene material, due to the strong interaction of van der Waals forces, the graphene layers are stacked and tend to be irreversibly stacked; mesoporous carbon, as a porous carbon material, has a larger surface area and fewer micropores than traditional carbon black materials. The preparation methods mainly include carbonization method, template method, activation method, CVD method and solution assembly method. Its preparation process is relatively complex and the production cost is high, which limits its large-scale application; carbon nanotubes are seamless hollow tubes made of graphene sheets formed by carbon atoms. Metal nanoparticles are not easily adsorbed on pure inert carbon nanotubes.
[0004] The carbon support materials reported at this stage still have various defects, and most of their preparation methods require high-temperature calcination and complicated process flows. Therefore, it is urgent to provide a solution to the above problems. Summary of the invention
[0005] The invention provides a platinum-based catalyst and a preparation method and application thereof. The catalyst uses polyphenols and s-triazine-based compounds as raw materials, synthesizes a nanorod-shaped carrier by a supramolecular self-assembly method, and then uses a reducing acid or a reducing alcohol to in-situ deposit platinum nanoparticles on the surface of the carrier. The finally prepared catalyst has extremely high activity and stability in catalyzing hydrogen production by the reducing acid or the reducing alcohol at room temperature and pressure, has a simple production process, is green and environmentally friendly, has low raw material prices, mild reaction conditions, low energy consumption, does not require the use of surfactants, and has good application prospects and economic benefits.
[0006] In a first aspect, the present invention provides a platinum-based catalyst, comprising a carrier and an active ingredient loaded on the surface of the carrier; the carrier is a polyphenol-s-triazine-based carrier; and the active ingredient comprises a platinum precursor.
[0007] The catalyst provided by the present invention has excellent performance in catalyzing the production of hydrogen from reducing acids and reducing alcohols, and also has good stability, corrosion resistance, electrical conductivity and strong mechanical strength.
[0008] Optionally, the polyphenol is selected from any one of tannic acid and gallic acid.
[0009] Optionally, the s-triazine group is selected from s-triazine group compounds, including any one of melamine and cyanuric acid.
[0010] Optionally, the platinum precursor is selected from any one of chloroplatinic acid and chloroplatinate.
[0011] Optionally, the molar ratio of the polyphenol to the s-triazine-based compound is 1:(1-100).
[0012] Optionally, the mass ratio of platinum in the platinum precursor to the carrier is (0.005-0.20):1.
[0013] In a second aspect, the present invention provides a method for preparing the above catalyst, comprising the following steps:
[0014] S1, in an alkaline solvent, polyphenols and s-triazine compounds are mixed and stirred to obtain a polyphenol-s-triazine carrier;
[0015] S2. In a solvent environment, add a platinum precursor to the carrier prepared in step S1, and perform ultrasonic treatment to obtain a platinum-based catalyst.
[0016] The carrier prepared by the preparation method provided by the present invention coordinates with platinum through functional groups such as amino, hydroxyl, and carbonyl groups, thereby improving the interaction force between the carrier and platinum nanoparticles, allowing the platinum nanoparticles to be evenly dispersed on the surface of the carrier, effectively inhibiting the agglomeration of platinum nanoparticles and controlling the size of platinum nanoparticles, thereby increasing the active sites of the catalyst catalytic reaction.
[0017] Optionally, step S1 comprises: stirring the polyphenol in an alkaline solvent for 0.1 h to 5 h in advance, adding an s-triazine compound and stirring for 0.5 h to 72 h to obtain a polyphenol-s-triazine carrier.
[0018] Optionally, the alkaline solvent in step S1 includes a Tris-HCl solution with a pH of 8.5 and a concentration of 0.1 mol / L to 5 mol / L.
[0019] Optionally, the solvent environment in step S2 includes 1 mol / L-10 mol / L of reducing acid or reducing alcohol.
[0020] Optionally, the reducing acid includes any one of formic acid and oxalic acid.
[0021] Optionally, the reducing alcohol includes any one of methanol and ethanol.
[0022] Optionally, the ultrasonication time in step S2 is 0.1h-2h.
[0023] Optionally, the products obtained in step S1 and step S2 need to be filtered, washed and dried.
[0024] Optionally, the drying comprises drying in an oven at 50° C.-150° C. for 4 h-12 h.
[0025] In a third aspect, the present invention provides use of a product prepared by any of the above optional preparation methods in catalyzing the decomposition of reducing acids or reducing alcohols to produce hydrogen.
[0026] The catalyst provided by the invention has good performance of thermally catalyzing formic acid to produce hydrogen at normal temperature and pressure, excellent electrical conductivity and strong resistance to carbon corrosion. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] In order to more clearly introduce the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments.
[0028] Figure 1 It is the technical roadmap for preparing platinum-based catalysts of the present invention;
[0029] Figure 2 is a SEM photograph of the tannic acid-melamine carrier prepared in Example 1 of the present invention;
[0030] Figure 3 is a SEM photograph of the platinum-based catalyst prepared in Example 1 of the present invention;
[0031] Figure 4 is the hydrogen production of formic acid decomposition produced by the platinum-based catalyst prepared in Example 1 of the present invention at room temperature;
[0032] Figure 5 is the XRD spectrum of the platinum-based catalyst prepared in Example 1 of the present invention and the platinum-based catalyst recovered after catalytic hydrogen production reaction;
[0033] Figure 6 FT-IR spectra of the platinum-based catalyst prepared in Example 1 of the present invention and the platinum-based catalyst recovered after catalytic hydrogen production reaction;
[0034] Figure 7It is the Raman spectrum of the platinum-based catalyst prepared in Example 1 of the present invention and the platinum-based catalyst recovered after catalytic hydrogen production reaction. DETAILED DESCRIPTION
[0035] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described through the following embodiments in conjunction with the accompanying drawings. However, the following embodiments are illustrative and are only used to specifically describe the present invention rather than to limit the present invention.
[0036] The present invention provides a platinum-based catalyst, which comprises a carrier and an active component loaded on the surface of the carrier; the carrier is a polyphenol-s-triazine-based carrier; and the active component comprises a platinum precursor.
[0037] In some embodiments, the polyphenols are selected from any one of tannic acid and gallic acid.
[0038] In some embodiments, the s-triazine group is selected from s-triazine group compounds, including any one of melamine and cyanuric acid.
[0039] In some embodiments, the platinum precursor is selected from any one of chloroplatinic acid and chloroplatinate.
[0040] In some embodiments, the molar ratio of the polyphenol to the s-triazine compound is 1:(1-100).
[0041] In some embodiments, the mass ratio of platinum in the platinum precursor to the carrier is (0.005-0.20):1.
[0042] See also Figure 1 The present invention also provides a method for preparing the catalyst, comprising the following steps:
[0043] S1. In an alkaline solvent, a polyphenol-s-triazine-based compound is mixed and stirred to obtain a polyphenol-s-triazine-based carrier;
[0044] S2. In a solvent environment, add a platinum precursor to the carrier prepared in step S1, and perform ultrasonic treatment to obtain a platinum-based catalyst.
[0045] In some embodiments, the alkaline solvent environment in step S1 includes a Tris-HCl solution with a pH of 8.5 and a concentration of 0.1 mol / L to 5 mol / L.
[0046] In fact, when executing step S1, the following sub-steps are included:
[0047] S1.1. Mix tris(hydroxymethyl)aminomethane, hydrochloric acid solution and deionized water to obtain a Tris-HCl solution; add polyphenol to the Tris-HCl solution and stir for 0.1h-5h, then add the s-triazine compound and stir for 0.5h-72h until a precipitate is precipitated to obtain a dispersion;
[0048] S1.2, after filtering the dispersion, wash it with deionized water for 3 times, and dry it in an oven at 50°C-150°C for 4h-12h to obtain a polyphenol-s-triazine-based carrier;
[0049] In some embodiments, the solvent environment in step S2 includes 1 mol / L-10 mol / L of reducing acid or reducing alcohol.
[0050] In some embodiments, the ultrasonic time in step S2 is 0.1h-2h.
[0051] In some embodiments, the product obtained in step S2 also needs to be filtered, washed and dried.
[0052] In some embodiments, the drying comprises drying in an oven at 50° C.-150° C. for 4 h-12 h.
[0053] The invention also provides application of the catalyst in catalyzing decomposition of reducing acid or reducing alcohol to produce hydrogen.
[0054] Example 1
[0055] See also Figure 1 Embodiment 1 of the present invention provides a method for preparing a platinum-based catalyst, comprising the following steps:
[0056] S1.1. Add 0.1962 g of tannic acid (TA, CAS: 1401-55-4) to a pH 8.5 Tris-HCl (CAS: 1185-53-1) buffer solution and stir for 0.5 h until completely dissolved. Then add 0.8 g of melamine (MA, CAS: 108-78-1) and stir for 10 h until a precipitate is formed to obtain a dispersion.
[0057] S1.2, after filtering the dispersion, washing it with deionized water for three times, and drying it in an oven at 60°C for 5 h to obtain a tannic acid-melamine carrier (TAMA);
[0058] S2, 2 mol / L formic acid solution, 50 mg of carrier and 4 mL of 1.936×10 -3 The mixture was mixed with a mol / L chloroplatinic acid solution and ultrasonicated for 0.5 h. The mixture was separated by suction filtration and washed with deionized water for three times. The mixture was then dried in an oven at 60° C. for 6 h to obtain a platinum-based catalyst (TAMA / Pt).
[0059] Performance Testing
[0060] (1) Morphology analysis
[0061] The TAMA carrier prepared in step S1.2 of Example 1 and the TAMA / Pt catalyst prepared in step S2 were characterized by SEM. The SEM photo of the TAMA carrier is shown in FIG. Figure 2 As shown in Figure 1, TAMA is observed to be a one-dimensional nanorod structure; the SEM image of TAMA / Pt catalyst is shown in Figure 1. Figure 3 As shown, it was found that Pt nanoparticles were uniformly loaded on TAMA nanorods and still maintained the original nanorod structure in a strong acid environment, indicating that TAMA nanorods have excellent carbon corrosion resistance, strong mechanical strength and good stability.
[0062] (2) Catalytic performance and stability
[0063] The TAMA / Pt catalyst prepared in Example 1 is used to catalyze the formic acid decomposition and hydrogen production reaction:
[0064] In a 500mL sealed Pyrex reaction bottle, 50mg TAMA was dispersed in 2mol / L formic acid solution and then chloroplatinic acid solution was added to maintain the total volume of the reaction solution at 100mL. After ultrasonic dispersion for 30min, nitrogen was bubbled for 25min to remove oxygen in the bottle. Stirring was maintained during the reaction. The hydrogen production was measured by gas chromatograph (TCD detector, nitrogen as carrier gas), and the test was performed every 0.5h. The reaction was continued for 3h. The formic acid solution and catalyst were not replaced during the reaction. Figure 4 As shown, the results show that TAMA / Pt catalyst exhibits excellent hydrogen production activity, and the catalytic activity does not decrease significantly after continuous reaction for 3 hours, indicating that TAMA / Pt is a relatively stable catalyst at room temperature.
[0065] The TAMA / Pt catalyst and the TAMA / Pt catalyst subjected to formic acid decomposition and hydrogen production reaction at room temperature for 3 h were characterized by XRD, FT-IR and Raman. Figure 5-7 The results show that the characteristic diffraction peaks, functional groups, D-band and G-band characteristic Raman peaks of the TAMA / Pt catalyst did not change significantly before and after the reaction, further indicating that the rod-shaped TAMA / Pt catalyst has carbon corrosion resistance, strong mechanical strength and good stability.
[0066] Although the embodiments of the present invention are described in detail above, it is obvious to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention as described in the claims. Moreover, the present invention described herein may have other embodiments and may be implemented or realized in a variety of ways.
Claims
1. A platinum-based catalyst, characterized in that The catalyst comprises a carrier and an active component loaded on the surface of the carrier; the carrier is a polyphenol-s-triazine-based carrier; and the active component comprises a platinum precursor.
2. The catalyst according to claim 1, characterized in that The polyphenol is selected from any one of tannic acid and gallic acid; the s-triazine group is selected from s-triazine compounds, including any one of melamine and cyanuric acid; the platinum precursor is selected from any one of chloroplatinic acid and chloroplatinate; the molar ratio of the polyphenol to the s-triazine compound is 1:(1-100); the mass ratio of platinum in the platinum precursor to the carrier is (0.005-0.20):
1.
3. A method for preparing the catalyst according to any one of claims 1 to 2, characterized in that: The following steps are involved: S1. In an alkaline solvent, polyphenols and s-triazine compounds are mixed and stirred to obtain a polyphenol-s-triazine carrier; S2. In a solvent environment, add a platinum precursor to the carrier prepared in step S1, and perform ultrasonic treatment to obtain a platinum-based catalyst.
4. The preparation method according to claim 3, characterized in that: Step S1 comprises: stirring the polyphenol in an alkaline solvent for 0.1 h to 5 h in advance, adding the s-triazine compound and stirring for 0.5 h to 72 h to obtain a polyphenol-s-triazine carrier.
5. The preparation method according to any one of claims 3 to 4, characterized in that: In step S1: the alkaline solvent includes a Tris-HCl solution with a pH of 8.5 and a concentration of 0.1 mol / L to 5 mol / L.
6. The preparation method according to claim 3, characterized in that: In step S2: the solvent environment includes 1 mol / L-10 mol / L reducing acid or reducing alcohol; the ultrasonic time is 0.1 h-2 h.
7. The preparation method according to claim 6, characterized in that: The reducing acid includes any one of formic acid and oxalic acid; the reducing alcohol includes any one of methanol and ethanol.
8. The preparation method according to claim 3, characterized in that: The products obtained in step S1 and step S2 need to be filtered, washed and dried; the drying includes drying in an oven at 50° C.-150° C. for 4 h-12 h.
9. Use of the catalyst according to any one of claims 1 to 2, or the catalyst prepared by the preparation method according to any one of claims 3 to 8, in catalyzing the decomposition of reducing acids or reducing alcohols to produce hydrogen.